TSUNAMI HAZARD EVALUATION METHOD AND DEVICE TO THIS END Russian patent published in 2008 - IPC G01V9/00 

FIELD: physics; measurements.

SUBSTANCE: present invention can be used in the field service for warning against tsunami waves. A detector is placed in the coastal area at a distance of 2-5 thousand kilometres from the shore. From the detector signals, the hazard level of the tsunami waves for the protected area is determined. A high frequency oscillation is generated on a radio buoy. Its phase is manipulated using a modulating code, containing information on the direction of propagation and hazard level of the tsunami waves for the protected area. The power of the generated complex signal with phase manipulation is amplified. The signal is broadcast with time interval determined by the hazard level of the tsunami wave for the protected area. At the ground station for receiving and processing signals, the frequency of received complex signal with phase manipulation is transformed. Its phase is doubled. The spectral width of the received signal with phase manipulation at an intermediate frequency and its second harmonic are measured. The results are compared, and if there is a considerable difference, synchronous detection of the received signal with phase manipulation at the intermediate frequency is carried out. Low frequency voltage is selected, proportional to the modulating code, and recorded. The reference voltage, necessary for synchronous detection of the received signal with phase manipulation at the intermediate frequency, is generated by selection of the second harmonic of the received signal with phase manipulation at the intermediate frequency, dividing its phase by two and selecting the harmonic voltage at the intermediate frequency. If the transmitted signal exceeds the three threshold values: "dangerous", "very dangerous", and "extremely dangerous", the tsunami is assigned the corresponding hazard levels. The harmonic voltage at the intermediate frequency, used as a base signal for synchronous detection of the received signal with phase manipulation at the intermediate frequency, before transmitted to the reference input of the phase detector, undergoes frequency detection. Short heteropolar pulses are selected, corresponding to moments in time when the phase of the reference voltage changes sharply from one state to another. These pulses are used for generating the control voltage. The pulses are affected by the phase of the reference voltage, which is stabilised in one state and the back-to-back effect is eliminated.

EFFECT: increased accuracy of obtained data.

2 cl, 5 dwg